You might try to blow out the brakes, you shouldn't have to pull the wheels you may have excessive brake dust since you been having problems with the brakes, this has helped me, good luck

Hello I did check voltage on battery and it was low, so brake seems like it was stuck which caused to over heat. I charged and serviced battery and that problem went away. It has not gotten to hot anymore. The problem I have now it seems like brakes are on cuz you hear like a grinding noise when moving forward or reverse. Battery is fully charged and getting right voltage out of it. Thank you for your responds.

That truck should have an AC drive motor, and if so and you are unaware do not attempt messing with its internals, it could be a bad inverter, dust in the motors preventing ventilation, your work area ambient temperatures.

Fan shroud covered by foreign debris. If operators are Pushing loads with the truck instead of picking them up you will have massive issues.

They are called Fork Lifts not Fork Push for a reason. I need more info to help more...